JPH11299206A - Brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the restriction of the outer diameter of a sensor magnet against the inner diameter of a stator and to improve productivity by fitting a spacer cylinder where one end is abutted on a step face part and a bearing on the other end and the sensor magnet is fixed to an outer periphery to a fitting face part. SOLUTION: A first fitting face part 6a fitting an end bracket side bearing 4 in an inserted state from one end side to the other end side, a large diameter part 6c whose diameter becomes larger than the first fitting face part 6a through a first step part 6b and a second fitting face part 6e whose diameter becomes smaller than the large diameter part 6c through a second step part 6d and to which a rotor magnet 7 is fixed are sequentially formed in a rotor axis 6. In the first fitting face part 6a, a spacer cylinder 11 is incorporated into a back side and the bearing 4 into an axis end side. The spacer cylinder 11 is formed to be thicker than the step H of the first step part 6b. The spacer cylinder where a sensor magnet 9 is previously fixed to an outer peripheral face becoming the first step part side is press-fitted and incorporated into the first fitting face part 6a until it abuts on the first step part 6b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of brushless motors used for electric components for vehicles and the like.

[0002]

2. Description of the Related Art Generally, a brushless motor 21 of this kind
As shown in FIG. 3, a rotor 24 having a rotor shaft 22 provided with a rotor magnet 23,
4, a stator 26 around which a stator coil 25 is wound on the inner peripheral surface of the motor casing so as to face the outer peripheral side, a sensor magnet 27 attached to the rotor shaft 22, and a position for detecting the position of the sensor magnet 27 It is configured to include members such as a detection sensor 28 and a terminal (not shown) for supplying power to the stator coil 25. By the way, in the conventional device shown in FIG. 3, the sensor magnet 27 is easily broken, so that it cannot be press-fitted to the rotor shaft 22 and is fixed in a state where it is positioned by bonding. . In order to position the sensor magnet 27, a small-diameter portion is formed on the rotor shaft 22 via the step surface portion 22a.
The sensor magnet 27 is attached in a state where the sensor magnet 27 abuts. In this case, the rotor shaft 22 is further axially supported by the end bracket 29 via a bearing 30.
In order to perform the positioning of 0, the rotor shaft 22 is further reduced in diameter through a step surface portion 22b. By the way, bearing 3
0 is preferably incorporated so as to appropriately secure the step surface portion abutting area and increase the shaft diameter of the bearing insertion portion to increase the bearing support strength. However, the rotor shaft 22 is attached by attaching the sensor magnet 27. Once the diameter has already been reduced, the diameter will be further reduced for mounting the bearing. As a result, the diameter of the bearing mounting portion of the rotor shaft cannot be reduced so much. It cannot be secured very large. In addition, if an attempt is made to secure a large abutment area for the stepped surface portion of the bearing 30, the rotor shaft 22 has
End becomes thin and the strength becomes weak. Alternatively, the rotor shaft 22 itself may be made thicker,
In that case, there is a problem that the motor becomes large. When the outer diameter of the sensor magnet 27 is larger than the inner diameter of the stator 25, the rotor shaft 22 can be assembled only from the end bracket 29 side. Alternatively, the size of the sensor magnet may be reduced, but in that case, the position detection accuracy is reduced. Further, it is conceivable to bond the sensor magnet 27 after the rotor shaft 22 is assembled. However, in this case, it is not possible to proceed to the next step until the adhesive force by the adhesive is secured to some extent, and the productivity is poor. is there. Therefore, as shown in FIG.
It is proposed that a thick spacer 33 be incorporated in the bearing mounting portion, and the bearing 34 be incorporated so as to abut against the spacer 33 to increase the abutting area of the bearing 34.

[0003]

In this case, however, in order to increase the abutment area of the bearing 34, the spacer 3 is required.
Although it is preferable that 3 has a large diameter, in this case, there is a problem that the mounting diameter position of the position detection sensor 36 is smaller than the outer diameter of the spacer 33 and the assemblability is significantly reduced. There is a problem that the present invention does not solve. In FIG. 4, the same reference numerals as those in FIG. 3 denote the same parts.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and aims to solve these problems. The present invention is directed to a motor case having a tubular shape, and a motor case formed on the motor case. An end bracket that covers the opening of the rotor, a rotor shaft rotatably supported by the motor case and the end bracket, a rotor magnet attached to the rotor shaft to form a rotor, and a diameter relative to the rotor magnet. A stator configured by winding a stator coil around an inner peripheral surface of a motor case so as to face the sensor direction, a sensor magnet attached to an end bracket side end of the rotor shaft, and a sensor magnet for detecting a position of the sensor magnet. A brushless motor comprising: a position detection sensor attached to an end bracket side; A spacer tube having a small-diameter mounting surface portion formed on the portion through a step surface portion, one end of which is in contact with the step surface portion, the other end of which is in contact with the bearing, and the outer periphery of which the sensor magnet is fixed is provided. It is attached. This eliminates the need to form a small-diameter stepped surface portion on the rotor shaft to mount the sensor magnet as in the conventional case, and can increase the contact area of the stepped surface portion of the bearing to increase the bearing support strength. be able to. In addition, the sensor magnet is integrally fixed on the outer circumference of the spacer cylinder in advance, and can be press-fitted onto the rotor shaft. It is not necessary to have an assembling step, and the outer diameter of the sensor magnet is not regulated with respect to the inner diameter of the stator, so that productivity can be improved.

[0005]

Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a brushless motor. The brushless motor 1 has a cylindrical motor case 2 having one end opened, and an end bracket 3 integrally attached to cover the opening of the motor case 2.
And front bracket 3a, both brackets 3,3
a and a rotor shaft 6 rotatably supported by the motor case 2 via bearings 4 and 5; a rotor magnet 7 attached to the outer periphery of the rotor shaft 6 to form a rotor; A stator 8 formed by winding a stator coil 8a around the inner peripheral surface of the motor case 2 so as to face the radial direction, a sensor magnet 9 attached to the end bracket side end of the rotor shaft 6, and the sensor magnet 9 comprises various member devices such as a position detection sensor (Hall element) 10 which is attached to the end bracket 3 via an attachment plate 10a so as to face the shaft 9 in the axial direction and detects the position of the sensor magnet 9. It is conventional.

The rotor shaft 6 has, from one end to the other end, a first mounting surface 6a for mounting the end bracket-side bearing 4 in an inserted state, and a first step 6b with respect to the first mounting surface 6a. A large-diameter portion 6c having a large diameter through the second step portion 6d, and a second mounting surface portion 6e having a small diameter with respect to the large-diameter portion 6c via a second step portion 6d, to which the rotor magnet 7 is fixed;
A third mounting surface portion 6g, which has a small diameter with respect to the second mounting surface portion 6e via a third step portion 6f, and to which the bearing 5 is mounted in a light press-fit state, is sequentially formed. And the first mounting surface 6
The present invention is implemented between a and the first step portion 6b. In other words, the spacer cylinder 11 is incorporated into the first mounting surface portion 6a on the back side and the bearing 4 is assembled on the shaft end side. The spacer cylinder 11 is formed to be thicker than the step H of the first step portion 6b, and The sensor magnet 9 previously fixed to the outer peripheral surface on the side of the first step portion is press-fitted into the first mounting surface portion 6a until it abuts against the first step portion 6b. On the other hand, the outer ring of the bearing 4 is fitted into the end bracket 3 in a light press-fitting manner, and the position detecting sensor 10 is mounted via the mounting plate 10a.
Is mounted, and the end bracket 3 is mounted and fixed to the motor case 2 in a state where the inner race of the bearing 4 is inserted into the first mounting surface portion 6a into which the spacer cylinder 11 is press-fitted. .

In the embodiment of the present invention configured as described above, the sensor magnet 9 is fixed to the spacer cylinder 11 in advance and is attached by incorporating the spacer cylinder 11 into the rotor shaft 6, so that the sensor magnet 9 is broken. It is not necessary to wait until the adhesive is solidified unlike the conventional device in which the sensor magnet 9 is adhered to the rotor shaft 6 with an adhesive because it is easy to press-fit, so that the spacer cylinder 11 is attached to the rotor shaft 6. After the press-fitting of the first mounting surface portion 6a, the process can immediately proceed to the next mounting process, and the workability of the mounting operation is improved. The bearing 4 is provided with a first stepped portion 6b.
As a result, it is not necessary to assemble the sensor magnet 9 with a diameter one step smaller than the sensor magnet mounting surface unlike the conventional one. Since it is directly mounted on the first mounting surface portion 6a to be mounted, the shaft diameter of the mounting portion of the bearing 4 as the rotor shaft 6 is maintained in a large diameter state, and the inner ring of the bearing 4 projects from the thick spacer cylinder 11. As a result, the abutting area of the bearing 4 is increased, and the support strength of the bearing can be improved. At the same time, since it is not necessary to provide a plurality of small diameter portions, it is possible to reduce the size of the motor without reducing the strength of the rotor shaft.

The present invention is, of course, not limited to the above-described embodiment, and the mounting surface formed on the rotor shaft 12 is different from that of the second embodiment shown in FIG. It can be implemented by setting the diameter as shown below. That is, the rotor shaft 12 is, from one end side to the other end side, a first mounting surface portion 12a on which the end bracket-side bearing 13 is mounted in an inserted state, and a first step portion 12b with respect to the first mounting surface portion 12a. A second mounting surface portion 12c to which the rotor magnet 14 is fixed, and a third mounting surface portion to which the bearing 15 is mounted in a lightly press-fit state with a small diameter via the second step portion 12d with respect to the second mounting surface portion 12c. 12e are sequentially formed. Then, similarly to the first embodiment, the spacer cylinder 17 to which the sensor magnet 16 is fixed in advance on the outer periphery may be press-fitted into the first mounting surface portion 12a until the spacer cylinder 17 abuts against the first step portion 12b.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view showing a first embodiment.

FIG. 2 is a sectional side view showing a second embodiment.

FIG. 3 is a sectional side view showing a conventional example.

FIG. 4 is a cross-sectional side view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brushless motor 3 End bracket 4 Bearing 5 Bearing 6 Rotor shaft 6a First mounting surface 6b First step 6c Large diameter portion 6d Second step 6e Second mounting surface 6f Third step 6g Third mounting surface 7 Rotor magnet 9 Sensor magnet 10 Position detection sensor 11 Spacer cylinder

Claims (2)

[Claims] 1. A motor case having a cylindrical shape, an end bracket for covering an opening formed in the motor case, a rotor shaft rotatably supported by the motor case and the end bracket, and a rotor shaft mounted on the rotor shaft. A rotor magnet forming a rotor, a stator formed by winding a stator coil around an inner peripheral surface of a motor case so as to radially face the rotor magnet, and an end bracket side of the rotor shaft. In a brushless motor including a sensor magnet attached to an end and a position detection sensor attached to an end bracket side for detecting the position of the sensor magnet, a stepped surface portion is provided on an end bracket side of the rotor shaft. Forming a small-diameter mounting surface portion, one end of which is in contact with the step surface portion, and the other end of which is in contact with the bearing, A brushless motor comprising a spacer cylinder having the sensor magnet fixed to an outer periphery thereof. 2. The method according to claim 1, wherein the spacer cylinder is
A brushless motor press-fitted into the rotor shaft.